The present disclosure relates systems and methods for detecting and monitoring patient conditions in clinical medicine settings.
Patients die unexpectedly on hospital wards under the careful watch of even knowledgeable and diligent healthcare workers at alarming rates. It has been argued that hospitals have a culture of failure tolerance. However, a more critical analysis reveals that this “tolerance” is actually resignation and that the high number of clinical failures comprises the unavoidable result of the ill-conceived attempt to manage the profound complexity of overlapping human pathophysiology without adequate technology. Unfortunately hundreds of common but subtle perturbations which combine to produce complex pathophysiologic failure cascades which progress to death can potentially occur with every patient in the hospital.
While the physiologic complexity of just one patient is often overwhelming, a single nurse may have twelve complex patients and a single hospitalist physician may have 30. In the present state of hospitals, most of the physiologic complexity resides in the electronic medical records (EMR) even as the patient progresses toward death. Unless an expert physician or nurse puts all the pieces together timely to see the evolving failure, the patient is often doomed even though healthcare workers are nearby.
Patient care in a hospital setting involves a complex management process because human pathophysiology is highly complex and healthcare workers address multiple patient issues simultaneously. Decisions about patient priority and care made by the healthcare workers are subjective to some degree and may vary depending on the level of expertise and experience of each person involved in patient care.
Because of the complexity involved in patient care, particularly in a hospital setting, healthcare workers have attempted to provide a level of uniformity to the process through protocol-based care. Such care may involve “if X-threshold-breach then Y-action” branching decision tree protocols. However, such protocols when considered in relation to the true level of pathophysiologic complexity often comprise a profound over simplification so that the healthcare worker can easily proceed down the wrong branch of a decision tree.
In addition to protocol-based care, healthcare workers often monitor various physiological parameters of a patient in order to obtain more information upon which they may base clinical care decisions. Many of these parameters may include blood oxygen levels, pulse rate, routine blood tests and vital sign tests, which may be recorded in a centralized electronic medical record. However, this testing may not be effective in the early detection of certain clinical conditions or in providing the healthcare worker with a clear picture of the patient's condition and care. Even subtle and minor levels of perturbation may lead to profound instability in certain clinical situations. For example, minor changes in the serum sodium in the setting of a stroke may lead to confusion and then obtundation, which may increase the risk of aspiration, pneumonia, and venous thrombosis. Indeed, the level of serum sodium decrement to produce such abnormalities may be as little as 8 mEq, a decrement which would otherwise not be likely to produce an adverse reaction in the absence of an acute stroke. Since an 8 mEq decline in serum sodium would normally be tolerated in the absence of a stroke, it may be easily overlooked as a cause of profound instability by a healthcare worker who may not be knowledgeable or diligent enough to recognize the entire relational complexity. It is very common that subtle or simple events or occurrences actually comprise linked components of a much larger, dangerous, but undetected expanding pathophysiologic failure process. Since simple pertubations are readily overlooked by the physician (or if they are identified, the pivotal linkage to other processes is commonly unrecognized), this allows the pathophysiologic failure process to progress, untreated toward death.
In another example of the challenges involved in the timely detection of evolving complex patient conditions, septic shock is often the end result of progression from the uncomplicated state of infection to progressive states of the inflammatory response syndrome, sepsis, severe sepsis, and finally septic shock. These distinctions of states are arbitrary and poorly defined at the bedside. The vast majority of patients have infection with fever without further progression and many even progresses to the inflammatory response syndrome without further progression to septic shock. Because routine blood testing and even continuous vital measurements may not always detect the pre-shock state, specialized blood tests and biomarker profiles specifically developed to detect the pre-septic shock state have been developed. However, specific blood test and profiles suffer from a lack of specificity, in part because the variable response of patients to physiologic perturbation. Whether or not a given patient progresses to shock depends on much more than the biomarkers present and their concentrations. Progression to shock may depend on a complex relationship of patient-specific physiologic responses to immunologic and inflammatory perturbation as well as the physiologic state of the patient at the onset and during the perturbation and the timeliness and adequacy of intervention (e.g. antibiotics and/or fluid). Since most of these factors are not captured by blood test measurements or biomarker profiles, even serial testing directed specifically toward the detection of the pre-shock state may not provide sufficient information to provide for reliable timely detection of the evolving state of severe sepsis or septic shock.